Science for Energy Flow

Energy Flow Diagram

This diagram shows 2010 energy flow from primary sources (oil, natural gas, coal, nuclear, and renewables) through transformations (electricity
generation) to end uses (transportation, industry, and residential, and commercial sectors). Oil provided the largest share of the 98 quads of primary energy
consumed, and most of it was used for transportation. Consumption of natural gas, the nation's second largest energy source, is split three ways—electricity
generation, industrial processing, and residential and commercial uses (mostly for heating). Coal, our third largest source, is used almost exclusively for
electricity. Nuclear energy and renewables each meet less than 10% of U.S. energy demand. Data are from the U.S. Energy Information Administration's Annual
Energy Review (www.eia.gov/aer/) and Lawrence Livermore National Laboratory (flowcharts.llnl.gov). Higher Resolution Image (1.6MB) )

19 MILLION BARRELS OF OIL CONSUMED DAILYAt $100 per barrel, this is roughly $2 billion of oil each day. 71% of U.S. oil consumption is for
transportation. The U.S. imports 50% of the oil it uses, more than any other country.

Oil, 36 Quads

83 PERCENTAGE OF ENERGY FROM FOSSIL FUELSMost of our energy supply comes from nonrenewable, carbon-intensive fossil fuels: oil, natural gas, and coal. Coal is the largest domestically produced energy source, but its use releases more CO2 per unit of energy compared to that
for oil or natural gas.

Natural Gas, 25 Quads

Coal, 21 Quads

104 NUCLEAR REACTORSLocated at 65 nuclear plants, 104 reactors provide almost 20% of the total net electricity generated in the U.S. Although the newest reactor entered commercial service in 1996, the U.S. generates more nuclear energy than any other country.

Nuclear, 8 Quads

10 PERCENTAGE OF ELECTRICITY FROM RENEWABLESBiomass and hydropower are the most heavily used renewable energy sources. For U.S. electricity generation, hydropower is the largest renewable source (6%), with wind, biomass, geothermal, and solar each providing about 1% or less.

160,000 MILES OF POWER LINES IN U.S. ELECTRIC GRIDThis "grid" of high-voltage transmission lines consists of three large interconnected systems with more than 10,000 generating units and 3,200 electric distribution utilities. About two-thirds of the 40 quads used to generate, transmit, and distribute electricity is lost at power plants and in power lines, resulting in 13 quads of utilized electricity

Electricity, 40 Quads

2010 U.S. Energy Consumption, 98 Quads42 Quads are used energy56 Quads are lost during conversion

3 TRILLION MILES TRAVELED ANNUALLYSome 235 million cars and light trucks covered most of the 3 trillion highway miles traveled in the U.S. each year. Light-duty vehicles use 60% of U.S. transportation energy. Heavy trucks (18%), aircraft (9%), and boats and ships (5%) account for most of the rest.

Transportation, 28 Quads

32 PERCENTAGE OF INDUSTRIAL ENERGY FOR REFININGPetroleum refining is the largest industrial consumer of energy. Other energy-intensive industries include chemical (24%), paper (11%), and metal (8%) manufacturing.

Industry, 30 Quads

113 MILLION HOMES USE 22% OF U.S. ENERGYSpace and water heating account for more than half of residential energy use. The typical U.S. family spends $2,000 a year on home utility bills.

77 PERCENTAGE OF COMMERCIAL ENERGY FROM ELECTRICITYThere are roughly 5.3 million commercial buildings in the U.S., including shopping malls and other retail space, offices, schools, hospitals, warehouses, and hotels. Lighting is the largest consumer of electricity in commercial properties and a key target for energy savings.